Modern design metal wireless call
Wireless doorbell for an apartment : Modern Design Metal Wireless Call
Quote from Article entitled Wireless doorbell for an apartment:
Pressing the button, acting as a transmitter, you send a radio signal to the receiver, which is a panel with a speaker. Using this bell, we must remember that radio waves are blocked or become weaker getting through the concrete structures. Therefore, if the walls of a house or an apartment are reinforced, or there is a metal mesh on the path of the signal, the device cannot operate. There are limitations in range the signal extends to. But it is at least 100 meters, so that the residents of private houses do not worry about it.
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